My vote would go towards getting an Avalon batch #3 order in. It seems appropriate to grow with the network using the best and most cost effective tech available at any given time.
I don't recommend this given the outrageously high price and the unpredictability of profitability depending on BFL / ASICMINER's deployment.
I agree that BFL / ASICMINER (and others) may change the game significantly. But then surely it is better to have more mining assets rather than more BTC sitting in cash doing nothing. If ASIC farms come online in the next few months then profitability will suffer regardless.
Price of Avalon batch #3 seems appropriate to me. BTC-wise it is in the middle of batch #1 and batch #2 as I understand. I don't bother with the USD comparison - surely the only way in which USD are relevant are in the operational cost of electricity.
I agree to a point, it's theoretically better to have additional gear on order than not, but there's always the possibility that a new player will bring gear to market priced in fiat or BFL will stop being BFLish.
Entertain this scenario for a second. We go all in on non-refundable Avalon batch 3 units. This yields us 5 more Avalons in a few months(+330Gh). All seems peachy...until BFL FINALLY gets their house in order and units start flying out the door. Now our wise purchase looks a whole lot less pretty because we could've hopped on their overly long order queue with a minirig order(+1.5Th). Even though the Avalons would almost surely arrive sooner, it'd likely be better to get the minirig later.